What is this "three arrows" special ability (navel)?

[Blkbird]

What is this special ability represented by the icon of three golden arrows in a circling triangle? "Sailing" is supposed to enable it on Coast and Astronomy is supposed to enable it on Ocean. Does anyone know what it is and where to find more information about it in the Civilopedia?

It seems this is the single special ability represented by a icon instead of text. Looks like a bug or at least carelessness by the developer.

 

[Dr. Zoidberg]

im pretty sure that it means that your trade routes extend over those squares. So if you and another civ have sailing, and two cities connected by coast, you''l be able to trade with each other.

 

[Blkbird]

im pretty sure that it means that your trade routes extend over those squares. So if you and another civ have sailing, and two cities connected by coast, you''l be able to trade with each other.

Trade route, yes, sounds very logical. And I remember the same thing in Civ3.

Edit: Now I'm no longer sure. I think it rather means "Contact" simply.

 

[Blkbird]

OK, I found it: Civilopedia > Game Concepts > City Network.

 

[Greek Plunder]

It basically just means you're all networked together, and you're able to trade, domestically and/or internationally. If a civ on the score counter has the symbol, it means you're able to trade with them.